/// <summary>
/// 初始化防止重复提交在Page_Load
/// 初始化之前要在前台加入一个隐藏域web控件<asp:HiddenField ID="HidSign" runat="server" />
/// <param name="_Page">Page对象</param>
/// <param name="_HiddenField">隐藏域对象ID</param>
/// </summary>
public static void Start_HidSign(System.Web.UI.Page _Page, System.Web.UI.WebControls.HiddenField _HiddenField)
{
string S_Sign = MathRandom.RandomDateTime(false, true).ToString() + MathRandom.RandomNumber(6);
_HiddenField.Value = S_Sign;
_Page.Session["WHidSign"] = S_Sign;
}
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="_Page">Page</param>
/// <param name="RandomLength">验证码的位数</param>
public static void RandomPic(System.Web.UI.Page _Page, int RandomLength)
{
//随机数
int Num = MathRandom.RandomNumber(RandomLength);
_Page.Session["WRandomNum"] = Num;
//创建Bmp位图
Bitmap bitMapImage = new Bitmap(RandomLength * 13 + 16, 24);
Graphics graphicImage = Graphics.FromImage(bitMapImage);
//设置画笔的输出质量
graphicImage.SmoothingMode = SmoothingMode.HighSpeed;
//添加文本字符串
graphicImage.DrawString(Num.ToString(), new Font("黑体", 18, FontStyle.Bold), new SolidBrush(Color.Red), new Point(2, 0));
//设置图像输出的格式
_Page.Response.ContentType = "image/jpeg";
//清空输出数据
_Page.Response.Clear();
//保存数据流
bitMapImage.Save(_Page.Response.OutputStream, ImageFormat.Jpeg);
//释放占用的资源
graphicImage.Dispose();
bitMapImage.Dispose();
}
